Some electric machines include a stator assembly and a rotor and are housed within a machine cavity. During operation of electric machines, a considerable amount of heat energy can by generated by both the stator and the rotor, as well as other components of the electric machine. As power output from electric machines continues to increase, there is a need to remove heat from the machine to maintain long-life and ensure reliability. Some electric machines are cooled by circulating a coolant through portions of the machine cavity. For example, the coolant can contact the rotor at a generally low tangential speed and then can be accelerated by a combination of friction with the rotor and radial movement further from a center line of rotation of the rotor. Conventional cooling methods can include removing the generated heat energy by circulating a coolant through inner walls of the housing or dispersing a coolant throughout the machine cavity of the housing.